pyes = ComputeWeibYN(x,alpha,beta)
Compute the value of a yes-no weibull psychometric function.
If ‘x’ is a matrix and the parameters are scalars, the same
psychometric function is applied to the whole matrix.
If ‘x’ is a matrix and the parameters are vectors, the
parameters are taken as applying to separate columns.
pyes = ( 1.0 - exp( - (x./alpha).^beta ) )
9/15/93 jms Added some special casing to deal with matrix inputs
with/without vectors of parameters